The tabby patterns are due to 3 distinct gene loci and one modifier:

At heterozygous gene loci, the two alleles interact to produce the phenotype.

On the number of the gene loci and the total mutation rate in man.

It is an arbitrary matter which, and how many, gene loci we choose to consider as a significant 'constellation'".

Second, for individual gene loci, a number of X-linked genes are common through mammalian species.

Most population genetics consider changes in the frequencies of alleles at a small number of gene loci.

When infinitesimal effects at a large number of gene loci are considered, one derives quantitative genetics.

The black color is caused by recessive gene loci.

The exact gene loci has not been characterized.

Locus heterogeneity means that variations in completely unrelated gene loci cause a single disorder.